This photo catches Senna looking quite happy at the 1992 Monaco Grand Prix, which he won that year.

Senna remained with McLaren in 1993 and moved to Williams in 1994. 

He was leading the 1994 San Marino Grand Prix at Imola when he went off the track on lap 7. A high-speed collision with the wall caused fatal injuries.

Senna had already scored three World Championships when he died and was still competitive enough to have potentially won more if he hadn't suffered the fatal crash.